Automatic change-over switch for wireless-telegraph receiving and sending apparatus.



I W. L. LEWIS. AUTOMATIC CHANGE-OVER SWITCH FOL. WIRELESS TELEGRAPH RECEIVING AND SENDING APPARATUS.

' APPLICATION FILED I'EB.14,1912. RENEWED JAN. 21, 1913. 1,074,057. Patented Sept. 23, 1913.

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W. L. LEWIS. AUTOMATIC CHANGE-OVER swncn FOR WIRELESS TELEGRAPH RECEIVING AND smmme APPARATUS. APPLICATION FILED FEB. 14, 1912. RENEWED JAN. 21, 1913.

1 74,057, Patented Sept. 23, 1913.

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WILLIAM L. LEWIS, 0F PHILADELPHIA, PENNSYLVANIA.

AUTOMATIC CHANGE-OVER SWITCH FOR WIRELESS-TELEGRAPH RECEIVING AND SENDING APPARATUS.

Specification of Letters Patent.

Application filed February 14, 1912, Serial No. 677,471- Renewed January 21, 1913. Serial No. 743,422.

To all whom, it may concern:

Be it known that 1, WILLIAM L. LEWIS, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented new and useful Improvements in Automatic Change-Over Switch for \Vireless-Telegraph Receiving and Sending Apparatus, of which the following is a specification.

This invention relates to the art of wireless telegraphy, and it has to do more especially with a change-over-switch whereby the. receiving or sending apparatus can be connected with the aerial to receive and send messages.

The invention has for its principal object to provide an automatic change-over switch which normally connects the aerial with the receiving instruments and is electrically operated by the sending key to connect the aerial with the sending instruments, the switch having an clectro-magnet which is in circuit with an electro-magnetic key or switch that opens and closes the primary circuit of the transformer, and the electromagnets of the switches are energized by the operators key, which is in a local circuit with the electro-magnets.

Another object of the invention is the combining with the change-over switch of means for automatically short-circuiting the detector of the receiving circuit so that danger of such detector being burned out during the operation of the sending instruments is overcome or its adjustment interfered with by the secondary current from the coil or transformer.

Another object of the invention is to provide an automatic change-over switch which saves the operator from the necessity of operating the large aerial switch now in common use, and furthermore the operator can interrupt a sending station if the latter makes a mistake or the receiving station cannot understand the message, as the receiving operator can operate the sending key at any time to inform the sending operator of his mistake or of his being misunderstood, as the aerial connection with the sending and receiving apparatus shifts automatically merely by the manipulation of the key.

\Vith these objects in view and others, as will appear as the description proceeds, the invention comprises the various novel features of construction and arrangement of parts which will be more fully described hereinafter and set forth with particularity in the claims appended hereto.

In the accompanying drawings, which illustrate one embodiment of the invention, Figure 1 is a diagrammatic view of the receiving and sending circuits of a wireless telegraph system. Fig. 2 is a plan view of the change-over switch with portions in section. Fig. 3 is a side view of the switch.

Similar reference characters are employed to designate corresponding parts throughout the views.

Referring to Figs. 2 and 3 of the drawing, the change-over switch will first be described. TlllS switch comprises a base 1 on which is mounted clectro-magncts 2 that have an armature 3 which is fastened to a pivoted switch arm 4, one end of the arm being formed with hearing lugs 5 through which extends a vertical pivot post 6 fastened in the base 1.. Around the portion of the pivot post between the lugs 5 is a helical torsional spring 7 which has one end 8 fastened to the upper lug and the lower end fastened to the pivot post, the tension of the spring being such as to hold the armature 3 away from the electro-magnets 2. The free end of the switch arm 4 carries contact points 9 and 10 that are adapted to engage adjustable contacts 11 and 12, respectively, mounted on posts 13 and 14, said posts being connected respectively with the receiving and sending apparatus by circuit wires 15 and 16. Carriedby and insulated from the switch arm 4 is a spring contact 17 which has a contact point 18 adapted to engage an adjustable and relatively fixed contact 19 mounted in a post 20, said post being connected by a wire 21 with the detector of the receiving circuit. The spring contact 17 is fastened to the switch arm by a screw 22 which passes through an opening in the spring contact and screws into an insulating bushing 23 fittedin an opening 24 in the switch arm 4, and interposed bet-ween the arm 4 and spring contact 17 is an insulating washer 25. This spring contact 17 is connected with a bindingpost or thelike 26 through a fiexiblefconductor or light spring 27, such binding post26 being connected by a wire 28 with "the; detector of the receiving station. .x'The fixed contact 19 has its tip projection through an opening 29 in the blade 4 so that the spring contact 17 can engage therewith when the electro-magnets 2 are energized. Normally, the switch arm 4, which is metallic and is connected by a wire 30 with the aerial, has its contact 9 engaging the-contact 11, while the contacts 10 and 18 are separated from the contacts 12.

and 19, ,respectively.- When the electromagnet becomes energized, the contact 9 separates from the contact 11 and the contacts 10 and 18 engage the contacts 12 and 19, respectively. This means that the receiving apparatus is out put of circuit and the sending apparatus cut into circuit with the aerial and at the same time the detector is short-circuited. As soon as the electromagnet is denergized, the switch arm 4 and spring 17 return to normal position.

The relation of the change-over switch to the sending and receiving apparatus is shown in Fig. 1, wherein the aerial A is connected by the wire .30 with the switch arm 4, and the wires 15 and 28 lead to the receiving helix or coil B and one terminal of the detector O,.respectively. The other terminal of the detector is connected by the wire 21 with the contact 19. The helix B is conn'ectedto ground at 31 and. associated with the helix is the usual receiving instrument D. The transmitting circuit consists of a transformer E that'has its secondary winding connected with the helix F; one terminal of which is grounded at 32. In the secondary circuit is the usual spark gap G and condensers H. The helix is connected with the change-over switch by the wire 16 that leads to the contact 12 of the change-over switch. Theprimary' circuit of the transformer is connected with the usual source of power (not shown) and includes an velectro-magnetic key or switch I, said switch having an electro-magnet '33 that is in series with the electro-magnets 2 of the change-over switch, such electromagnets being in a local circuit that includes the operators key 34 and a battery or other source of current 35. Normally, the receiving apparatus is connected with the aerial A'through the wire 30, arm 4 of and key I.

the change-over switch, contact 11, and wire 15 so that messages can be received from a sending station.

hen the operator desires to send a message, he manipulates the telegraph key 34 in the usual manner, according to any given code system. The making and breaking of the local circuit that includes the battery 35 will energize and denergize the electromagnets 2 and 33 of the c'hange-overswitch The electro-magnets of the change-over switch thus connect the aerial with the sending apparatus, which is energized and operated in the usual manner by the closing and opening of the primary circuit by the electro-magneticallyoperated key I that takes the place of the usual sending key. The; advantages flowing from the use of the change-over switch and arrangement of controlling circuits therefor will be readily appreciated.

From the foregoing description, taken in connection with the accompanying drawings, the advantages of the construction and of the method of operation will be readily apparent to those skilled in the art to which the invention appertains, and while I have described the principle of operation of the invention, together with the apparatus which I now consider to be the best embodiment thereof, I desire to have it understood that the apparatus shown is merely illustrative, and that such changes may be made when desired as are within the scope of the claims appended hereto.

Having thus described the invention, what I claim is I v i p 1. In a wirelesstelegraph system including transmitting and receiving apparatus, a change-over switch comprising a movable contact connected to the aerial, a stationary contact connected to the transmitting apparatus, a second stationary contactconnected tact adapted normally to be in engagement with the second stationary-contact, an electro-magnet" adapted upon being energized to bring said movable contact into engagement with the first stationary contact, said electro-magnet being in circuit with the key of the transmitting apparatus, means carried by the switch for short circuiting the receivingapparatus upon said movable contact being brought into engagement with thefirst stationary contact.

. 2. Ina wireless telegraph system including transmitting and receiving apparatus, a

contact connected to the aerial,.an adjustable contact connected to the transmittingapparatus, a second adjustable contact connected to the receiving apparatus, means for holding said movable contact normally in engagement with the second adjustable change-over switch comprising :a movable.

contact, means controlled by the key of the transmitting apparatus for bringing the movable contact into engagement with the first adjustable contact, a spring contact carried by the movable contact and insulated therefrom, and a third adjustable contact adapted to be engaged by the spring contact upon the movable contact being in engagement with the first adjustable contact said spring contact and third adjustable contact 10 being in a normally open circuit in shunt with the receiving apparatus.

In testimony whereof I afiix my signature in presence of two witnesses.

WILLIAM L. LEWIS. Witnesses:

Joe. R. C. WARD, WILLIAM A. LEWIS.

Copies of this patent may he obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. 0. 

